Expression Of MMP-9 After Cerebral Ischemic Reperfusion And The Effects Of Artificial Synthetic E-selectin In Rats

Objective: To study the mechanisms of tumor necrosis factor-αand matrix metalloproteinases -9 in rat brain suffured with ischemia-reperfusion injury and to further explore the protective mechanism of artificial synthetic E-selectin in cerebral ischemia-reperfusion injury model of rats.Methods: Healthy male Sprague-Dawley rats, weighing 250-300g, were randomly divided into 3 groups: operation group, sham operation group, and artificial synthetic E-selectin treated group, with 36 in each group. The cerebral ischemia- reperfusion injury model was established by inserting thread into middle cerebral artery. The procedure to establish sham operation group was similar to operation group but without inserting thread into middle cerebral artery. The treated group was established by the same method with operation group after that artificial synthetic E-selectin was injected into the femoral vein at 5 minutes preoperation . The neurological behavior scores of operation and treated group were evaluated postoperation, and the rat with 1-3 score was selected into experimental model. Samples were divided into 6 groups (2h, 6h, 12h, 24h, 48 and 72h after reperfusion). The contents of tumor necrosis factor-αand matrix metalloproteinases -9 expression in rat brain were measured by immunohistochemical methods, and matrix metalloproteinase-9 mRNA was detected by reverse transcription -PCR. The experimental data were analysised by the Statistical Analysis System version 8.0 software, and were tested at the level of hypothesis testα= 0.05 andα= 0.01 respectively.Results: The sham operation group: The expression of TNF-α, MMP-9 and MMP-9 mRNA were very small at different time points, and invaried with time going. Operation group: It was found that TNF-αappeared at 2h postoperation, increased at 6 and 12h, reached peak at 24h , and then decreased gradually at 48 and 72h. The expression of TNF-αin operation group was more than sham operation group ( P <0.01) at each time point. MMP-9 was detected at 6h postoperation, reached peak at 24h, and then decreased gradually at 48 and 72h. The expression of MMP-9 in operation group was more than sham operation group ( P<0.01) at each time point but at 2h postoperation. (P>0.05). MMP-9mRNA were also detected at 6h postoperation, reached peak at 24h, and then decreased gradually at 48 and 72h. The expression of MMP-9mRNA in operation group was more than sham operation group ( P<0.01) at each time point but at 2h postoperation (P>0.05). The varied trendcy of TNF-αin artificial synthetic E-selectin treated group was the same as operation group, but decreased much obvious at each time point (P<0.01). It showed the similar results with MMP-9 mRNA and protein expression but at 2h postoperation.Conclusions: 1. TNF-αinduces MMP-9 expression at transcriptional level in rats suffered with cerebral ischemia-reperfusion injury. 2. Artificial synthetic E-selectin can protect the ischemic brain tissue by decrease the expression of MMP-9. 3. The protection mechanism of artificial synthetic E-selectin for cerebral ischemia-reperfusion injury is probably that it inhibits the synthesis of MMP-9mRNA which is induced by TNF-αat the transcriptional level, resulting in decreasing the expression of MMP-9.